Actinotaenium riethiiImage © Alfred van Geest

Actinotaenium riethii. Notice subelliptic outline of the cell (rather than fusiform as in A. curtum).

Cell dimensions (L x B): 48 x 26 µm

 

 

Desmid of the month
January 2018

Actinotaenium riethii

Actinotaenium riethii was only recently described (Šťastný & Kouwets 2012). In rough outline it resembles A. curtum. Compared to that latter species, however, semicells in A. riethii less attenuate towards the poles and cell wall pores are much more densely set. A. riethii is found in a similar habitat as A. curtum, i.e., in ephemeral puddles, often on arteficial substrate that periodically may dry out. Thus far, in the Netherlands, A. riethii is only known from a few sites but presumably is rather widely distributed.

Reference:
Šťastný, J. & Kouwets, F.A.C., 2012. New and remarkable desmids (Zygnematophyceae, Streptophyta) from Europe: taxonomical notes based on LM and SEM observations. Fottea 12: 293-313.

Actinotaenium riethiiMouse over images © Alfred van Geest

Another cell of A. riethii showing a stelloid chloroplast.

A. riethii, empty cellMouse over Images © Alfred van Geest

Dead, largely empty cell of A. riethii showing closely set, fine cell wall pores.

Image © Jan Šťastný

SEM-picture of A. riethii. Notice closely set cell wall pores.

Image © Jan Šťastný

SEM picture of A. riethii (up) and A. curtum (down). Notice difference in cell shape and in density of the cell wall pores.